Binding of Staphylococcus aureus Protein A to von Willebrand Factor Is Regulated by Mechanical Force

Abstract

Staphylococcus aureus protein A (SpA) binds to von Willebrand factor (vWF) under flow. While vWF binding to SpA plays a role in S. aureus adherence to platelets and endothelial cells under shear stress, the molecular basis of this stress-dependent interaction has not yet been elucidated. Here we show that the SpA-vWF interaction is regulated by a new force-dependent mechanism. The results suggest that mechanical extension of vWF may lead to the exposure of a high-affinity cryptic SpA-binding site, consistent with the shear force-controlled functions of vWF. Moreover, strong binding may be promoted by force-induced structural changes in the SpA domains. This study highlights the role of mechanoregulation in controlling the adhesion of S. aureus and shows promise for the design of small inhibitors capable of blocking colonization under high shear stress.